1. Technical Field
The present invention relates to an image forming apparatus.
For example, as image forming apparatuses that display images on a surface of a screen or the like, optical scanning-type projectors are widely known (for example, see JP-A-2007-199251).
2. Related Art
An optical scanning-type projector disclosed in JP-A-2007-199251 has a light source that emits laser beams of a desired color at a desired timing and a polarizing unit that two-dimensionally scans the laser beams emitted from the light source. In addition, the polarizing unit has a first optical scanner that scans laser beams in the horizontal direction and a second optical scanner that scans laser beams in the vertical direction. Each of these two optical scanners has a mirror that reflects the laser beams and is configured to scan the laser beams by turning the mirror around a predetermined axis. Such an optical scanning-type projector is configured so as to display a desired image on the screen by performing a two-dimensional scanning process in which laser beams are scanned by the first optical scanner, and then laser beams are scanned by the second optical scanner.
The optical scanning-type projector disclosed in JP-A-2007-199251 is driven such that the swing widths of the first and second optical scanners are maintained at set values for any image regardless of the size of the image displayed on the screen. Accordingly, for example, even in a case where the width of an image (hereinafter, also referred to as a “display image”) displayed on the screen in the horizontal direction is far smaller than the swing width of the first optical scanner or the width of the image in the vertical direction is far smaller than the swing width of the second optical scanner, the first optical scanner and the second optical scanner need to be turned with a large swing width with respect to the display image.
According to such a driving method, the time interval required for displaying one image is unnecessarily lengthened. As a result, the number of images that can be displayed (drawn) per unit time is decreased. Consequently, there is a problem in that variations in the image displayed on the screen occur or a moving picture cannot be reproduced smoothly. Furthermore, there is a problem in that more power is consumed than necessary.